Casio 407M-52 / H104 Manual — Modules 82 / 142

One owner's manual PDF for the Casio module 82 in English. Casio fitted it in 6 models, including the 407M-52 and H104 — the full list is below. The same document also covers module 142. For module 82, Casio's spec sheet lists one BR2016, with 2 years of battery life and accuracy within ±15 seconds a month; the module first shipped in Nov 1980.